Storing Alternate User Identifiers

HealthVault

For current versions of HealthVault, offline applications must store
the correspondence between the application’s concept of a user identity
(typically some sort of id) and the HealthVault identity of a user
(person id and record id). In many cases this is straightforward but some
applications may not have a convenient place to store this information.
Alternate ID support provides a way for applications to store this
correlation in HealthVault.